1. Technical Field
The present invention relates to a distributed restoration method for link- or node-failure within a communication network, and a related system.
2. Discussion of Related Art
Such a distributed restoration method and related system are already known in the art, e.g. from the article "Double Search Self-Healing Algorithm and its Characteristics " from the authors H. Fujii and N. Yoshikai from NTT Telecommunications Network Laboratories. This article is published in "Electronics and Communications in Japan", Part 1, Volume 77, No. 3, 1994, Page 75-86. The article is translated from Denahi Joho Taushin Gakkai Ronbunschi, Vol. 76-B-1, No. 7, July 1993, pp.485-495.
Therein, a communication network is described consisting of a plurality of Network Elements, called nodes, interconnected by Network links, called links. Along these Network links a communication-path, or a path in the article, is set up between each couple of communicating nodes. If a failure occurs, on such a communication path, a system for distributed restoration will recover this communication-path.
During introduction of a distributed restoration system in an entire communications-network comprising a number of Network Elements, no distributed restoration for the complete communications-network can be provided because the introduction of such a distributed restoration system will in general not take place at once but only in a gradual way, Network Element by Network Element. Moreover in communication-networks that are built up of different kinds of Network Elements, e.g. in multivendor or multi-operator environments, distributed restoration may not be supported throughout the entire network since the different Elements may not be compatible.